Clutch plate



Feb.- 12, 1935. c.. G. woon 1,990,683

CLUTCH PLATE Filed Aug. 21, 1953' INVENTOR.

ATTORNEYS.

Patented Feb. 12, 1935 UNITED STATES PATENT OFFICE CLUTCH PLATE '4 ClarencevG. Wood, Cleveland Heights, Ohio Application August 21, 1933, SerialNo. 685,997

s Claims. (o1. isz- 68) The present invention relating, as indicated, to clutch plates has more precise reference to that particular part of a clutch assembly which is adapted to intermittently vtransmit torque from a driving flange to a driven shaft. It is contemplated that the clutch plate embodying'the principle of my invention be best adaptedfor'use in an-internal combustionengine clutch assembly and that such clutch plate be positioned between the ii'ywheel and pressure engaging means known asthe pressure plate.

Since it is the maj orfu'nction of a clutch plate v to transmit torque from a power source to a torque resistant element,'such as a propeller shaft of an automobile, -i t is necessary that means be provided to impart a cushioning eie'ct to such a torque transmitting element. In an Vautomobile particularly the vibrations which are imposed upon the crank shaft by the irregular impulses of the cylinders and the'back-lash from the rear wheels upon the propeller shaft become-concentrated at the clutch. Accordingly, a so'called flexible center clutch plate functions as a vibra. tion dampener. combustionengine increases veryrapidly with respect to the velocity offthe engine, it is paramount that a vibration dampener, which is intended to transmit such torque, possess a similar rate of torque resistance.Y Therefore, it is one of the objectsof my invention toprovide a novel form of construction forv incorporating resilient or spring elements between the hub and disk of a clutch plate in which the increase in spring in' order that a' maximum cushioning eiect will A be obtained with a minimum movement of` the parts; andto provide such a cushioning element which-will posses's'the advantages of eflicient operation and durability. l

Other objects and advantages of the invention will become apparent as the'following descrlptionp'roceeds. i Y' To the accomplishment of `the foregoing and related ends, said invention, then, consists of the means hereinafter fully describedand particularly pointed out in the claims, the annexed drawing and the following description setting forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, 'but one of various mechanical forms in Which'the principle of the invention may be used.

In said annexed drawing:-

Fig. 1 is a plan View of the clutch plate em- Since the torque of an internalY bodying the principle of my invention; Fig. 2 is a transverse Asection of Fig-1 taken substantially along line 2-2 thereof; Fig.'3 is a view illustrating the principle of operation of the spring vto which there is attached on either side the friction facing'rings 2 and 3. Suitable rivet fasteners 4 may be provided in order to secure the facing rings 2 and V3 to the face of the disk 1. facing rings 2 and 3 are adapted to be intermittently contacted by the flywheel and the pressure plate of the clutch assembly. Such a latter assembly, being well known in the art,`is therefore not illustrated. A splined hub 5 is positioned centrally of vthe disk 1. The hub 5 is adapted to engage with the stub shaft of the Vclutch and constitutes the driven member of the clutch plate. The hub 5 is made movable, with respect to the disklbody 1. AReinforcing plates 6 and 7 are secured to the disk body 1 adjacent the outer periphery of the hub 5. There is a series of recesses 8 formed inthe inner periphery of the disk 1 and the reinforcing plates 6 andrl. Similarly there are a plurality of recesses 9 formed in the Y outer periphery of the hub. 5. The recesses 8 and 9 are positioned in radial registry with respect to each other. Spring elements composed of the relatively thin leaves 10 and the relatively thick leaves 11 are received in the recesses 8 and 9. 'I'he thicker spring leaves 11 are disposed on the outer sides of the laminated spring elements and extend only as far as the outer periphery of the hub 5. The outer edges of the recesses 8 and 9 are curved as shown at the points 12 and 13. The cover plates 15 and 16 are secured in position by suitable fasteners such as the rivets 17.

V The operation of the above described construction is substantially as follows: When torque is suddenly applied to the clutch plate, it would be transmitted from the disk 1 to the hub 5. Since the hub 5 is joined to the disk 1 onlyby means of the resilient laminated springs, there will resulta iiexing or bending action upon thersprings which will tend to absorb the sudden application of torque and thereby produce a cushioning effect. By reason of the fact that the relativelyY heavy leaves are positioned on the outside of the laminated spring elements, the bending action during the transmission of torque will be trans- The1 .200 foot-pounds.

ferred throughout a greater area of the thinner leaves 10 than would be the case if the heavy leaves 11 were not present. This latter action is well illustrated in Fig. 5. In other words, whenever a laminated spring element composed of uniform thicknesses of leaves is subjected to a bending movement, there is a tendency for the strain to concentrate at one point which is the longitudinal center of the laminated spring element. However, when the heavier outside leaves 1=l are present,- such a concentration of bending strain will have a tendency to be distributed throughout a greater area of the spring.

element and will not be concentrated at a single point where premature failure would occur.

Directing attention to Figs. 4-and 5, when relative movement between the disk land hub 5 rst occurs, that is, upon initial clutch engagemenmthe lower or inner ends of the thin leaveswill be iiexed over a relatively short length, as indicated by the numeral 18. The heavier leaves ll will not be subjected to bending action upon initial movement. It will also be seen that since the thin leaves l are bent over a relatively short portion of their length that the bending leverage issmall and that there will resulta relatively stiil spring action. This means that the clutch Aplate upon initial movement oiers a maximum spring resistance in proportionto such. movement. Asthe applied torque is increased and greater relative movementbetween the hub anddisk l` occurs, the spring elements will assume a bending deformation, asshown in Fig. 5. In this latter view the thin leaves have been vflexed over a relatively greater length, as indicated by the numeral 18?. The thick leaves-are alsov subjected toa Ybending over their end portions, as.` indicated by the numeral 19. In other words, a-cumulative spring resistance hasbeen set up which isv substantially similar to the rate of. torque increase.

It is of utmost importanceV that the above described spring action be present in the clutch plate. In theA majority of automobiles theintial torque application amounts to about 40:01 y550 foot-pounds, increasing to a maximum of 140v to Therefore, if a springelement, which is adapted to absorb and,e .transmit .such

torque, has a relatively weak initial spring resistance, it will be seen that the sudden-application of torque will flexthe springto a maximum, and then when the torque Vresistance of the drivenelement is-overcome and becomes substantially equal to that of the torque applied, there will result an oscillating effect due to the tendency of such a- Weak spring element to return to its unilexed` position. That is to say, where the rate of change of springresistanceis not substantially similar tov the rate of change of the torque applied, the vibrational eil-ect will be aggravated rather than eliminated.

The rounded edges 12 and 13 uponthe recesses 8 andI 9 also; serve an Aadvantageous function in that they' produce a wedging rather than a-shearing action upon thespring elements.A tunction is illustrated in Fig. 3 in which have been shown sections of two external gears V29. and. 21 having. tangential outer pe-ripheries. Two at strips 22 havebeen inserted between the teeth of the gears 20 and 2l and it will be. seenthat these pieces 22 areY functioning as wedge ymembers against the edges of the teeth when the gears are rotated in opposite directions.. This-latter action, as illustratedin Fig-3, is substantially analogous to the action that takesplace between thedisk. 1 and the hub 5. That is to-say, the spring, elements positioned in the recesses which have rounded edges corresponding to the rounded edges of the gear teeth serve as wedging elements when the disk 1 and hub 5 are approaching a point of maximum movement. Therefore, it is apparent that the torque absorbing or cushioning action, which is present in my clutch plate, is dependent both upon the resilient bending force of the spring elements as well as a Wedging action.

The above described clutchplate. construction is ofV particular advantage aninternal combustion engine vehicle in which the repeated shocks of` torque transmission are numerous and severe,

Other forms may be employed embodying the features of my invention instead of the one here explained, change being made in the form or construction, provided the elements stated by any of the ollowing claims or the equivalent of such stated elements be employed.

I therefore particularly point out and distinctly claimas'my invention:--

1. In a clutch plate, the combination of a disk member, a hub-member centrally disposed in said disk member and movable with respect thereto,

.a series of laminated spring elements having each end anchored in said hub member and saidv disk member respectively, said spring elements includingrelativelyv thick andl heavy leaves disposed on their'outer sides, said last-named. leaves remaining unflexed upon initial relative movement of said disc and hub members, and being adapted to flex. ony further and final relative movement thereof.

2.. Ina-clutch plate, the combination of a disk member, a hub member centrally disposed in said disk-member and movable withfrespect thereto, a. series1 of laminated spring elements havingv each endY anchored in said hub member and said disk member respectively, said/springv elements being composedA of avplurality of relatively thin leaves .in-the medial Vportion and relatively thick leaves disposed on their4 outer sides,l said thin leaves only being. adaptedlto ex on initial relative movement of said disc andhub members, .and all of said leaves being. adapted to ex on further and finalv relative movement thereof.

3. InY a clutchV plate, the combination of a disk member,.a hubmember centrally disposed in said disk member andmovable with respect thereto, a series of laminated spring elements having each end anchored in said hub member and said disk member respectively, said spring, elementsincluding relatively thick and heavy leaves disposed on their outer sidesand. only one end of said heavy leaves being. secured to said disk member, ,the other end-'being free to ex.

4.v Ina clutch plate, the combination of s, disk members ahub member centrally disposed in said disk member and movable with respect thereto, a 'series` of laminated spring elements'having each end anchored in said hub member and said disk Vmember respectively',lsaid. spring elements being .composed of a plurality of relatively thin leaves in the medial portion and relatively thick leaves disposed von their outer ends, said thick leaves being substantially shorter than said thin leaves and having. one end free to flex.

5.v In a .clutch plate, ythe combination of a disk .membena hub member centrally disposed in said disk member and movable with respect thereto,

plurality of flat leaves, including relatively thick leaves disposed on the outer sides, said last-named leaves remaining unflexed upon initial relative movement of said disc and hub members, and being adapted to flex on further and nal rela-l tive movement thereof. l Y

6. In a clutch plate, the combination of a disk member, a hub member centrally disposed in said disk member and movable with respect thereto, oppositely disposed radial recesses in said disk and hub members respectively, spring elements having each end engaging with said recesses, and rounded shoulders on the outer edges of said recesses, said spring elements being composed of a plurality of relatively thin leaves in the medial portion and relatively thick leaves disposed on the outer sides, said thin leaves only being adapted to flex on initial relative movement of said disc and hub members, and all of said leaves being adapted to flex on further and iinal relative movement thereof.

7. In a clutch plate, the combination ofa disk member, a hub member .centrally disposed in said disk member and movable with respect thereto,

Voppositely disposed radial recesses in said disk and hub members respectively, spring elements having each end engaging with said recesses, and rounded shoulders on the outer edges of said recesses, said spring elements being composed of a plurality of relatively thin leaves in the medial portion and relatively thick leaves disposed on the outer sides and only one end of said heavy leaves being secured to said disk member, the other end being free to ilex.

8. In a clutch plate, the combination of a disk member, a hub member centrally disposed in said disk member and movable with respect thereto, oppositely disposed radial recesses in said disk and hub members respectively, spring elements having each end engaging with said recesses, and rounded shoulders on the outer edges of said recesses, said spring elements being composed of a plurality of relatively thin leaves in the medial portion and relatively thick leaves disposed on the outer sides, said thick leaves being substantially shorter than said thin'leaves and having one end free to iiex.

CLARENCE G. WOOD. 

